Apparatus and method for controlling the weight of fabric produced by a textile machine, in particular by a circular knitting machine

ABSTRACT

An apparatus ( 1 ) is provided to control the weight of fabric produced by a textile machine ( 2 ), comprising weighting means ( 11 ) of every single fabric piece directly associated to the textile machine dedicated to the manufacture of the same. A procedure is also provided to control the weight of the fabric produced by a textile machine comprising a weighting stage of every single fabric wounded or folded, near the textile machine dedicated to the manufacture of said piece, and to apply to every manufactured piece a printed label suitable to provide at least specific data concerning the piece weight.

BACKGROUND OF THE INVENTION

The object of the present invention is an apparatus and method forcontrolling the weight of fabric produced by a textile machine, inparticular by a circular textile machine.

As is known, textile machines, and in particular circular knittingmachines for manufacturing knitted fabrics, are generally provided witha pick-up unit for the produced fabric piece, said unit being equipped,beyond with suitable traction rolls, with a winding roll in case thepiece is picked up in rolls, or with a cloth folder in case said pieceis picked up in laps.

In the case of circular knitted machines the pick-up unit consists of astructure turning integrally with the cylinder or needle bed placedabove it together with the stretching rolls positioned upstream fromsaid pick-up unit. The rotary motion of the stretching and pick-up unitand of the needle bed usually consists of a mechanical unit or, in morerecent times, said motion is driven by an electric motor enslaved in itsturn with an electronic unit controlling the correct working of everyportion of the textile machine.

Since all the fabric pieces, either folded into rolls or piled up inlaps, coming out of a knitting mill and successively sent to otherdepartments or factories for finishing or dyeing operations must beassigned their effective weight, it is provided in the prior art toweigh each individual piece in a suitable weighing department.

In practice, some pieces produced by a given textile machine are piledup beside said machine and then periodically picked up and conveyedtogether with other groups of pieces coming from other machines to theweighing department, in which the weight of each piece is written downdirectly onto an edge of the fabric or on a card which should obviouslybe attached to the weighed piece.

Moreover, the weight of each piece should then be written down onto asummary form.

The weighing process briefly described above shows a number ofdisadvantages.

First of all, pieces have weights which can strongly vary with respectto the foreseen values, since the evaluation of the weight of a givenpiece during its production is generally carried out on the basis of thenumber of revolutions made by the knitting machine during itsmanufacture. According to the moisture degree, to the kind of yarn andto the knitted structure, highly different weights having the samenumber of revolutions and sometimes even going beyond the admissibletolerance field can correspond.

In addition, technical times directly required for the detection of theweight of fabric pieces and times required for their conveyance to theweighing departments are quite long.

The specific personnel is therefore partially diverted from carrying outmore specifically manufacturing operations connected with the working oftextile machines.

It should be observed that the conveyance and storing in the same placeof several pieces coming from different machines can easily involve anexchange between similar pieces assigning to them features, such as thekind of yarn and the batch of raw materials used, which do notcorrespond to the actual features, thus clearly creating problems in thehandling of the produced fabrics.

It should eventually be pointed out that the practice to put anindelible mark directly onto an edge of the fabric, which cannottherefore be used, can involve high economic losses in the case ofvaluable textile fibers.

In this situation the technical purpose of the present invention is toprovide an apparatus and a method for controlling the weight of fabricproduced by a textile machine which can substantially overcome theabove-mentioned disadvantages.

Within said technical purpose an important aim of the invention is toprovide an apparatus and a method allowing to obtain at the output ofthe textile machines wound or folded fabric pieces showing—with anextremely reduced tolerance field—a pre-established weight,independently from the kind of yarn, and therefore to reach for Instancehigh degrees of homogeneity of the unfinished products which should thenundergo finishing or dyeing operations. Another important aim of theinvention is to provide an apparatus and a method allowing to assignwith certainty to every piece of manufactured fabric not only its actualweight, but also every other information which could be useful todistinguish it, such as the kind of yarn, the presence of possibledefects due to machine stops, and the moisture degree at which thefabric-building process took place, thus avoiding information exchangesamong the various fabric pieces due to operators' faults or otherreasons.

SUMMARY OF THE INVENTION

A further aim is to provide an apparatus and a method showing the weightof a given fabric piece immediately at the end of its manufacturingprocess, thus eliminating dead times required in the prior art becauseof the weighing operations.

The technical purpose and the aims indicates are substantially reachedby means of an apparatus and a method for controlling the weight offabric produced by a textile machine, characterized in that theycomprise one or more technical solutions claimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The description of some preferred though not exclusive embodiments of anapparatus for controlling the weight of fabric produced by a textilemachine according to the invention is now disclosed as a merenon-limiting example, as shown in the enclosed drawings, in which:

FIG. 1 shows a perspective view of a first apparatus according to theinvention associated with a circular textile machine, the latter beingonly partially represented;

FIG. 2 shows a front view of the apparatus and of the machine shown inFIG. 1;

FIG. 3 is a detail of an enlarged vertical section of the apparatusshown in FIG. 1;

FIG. 4 is a broken perspective view of a second embodiment of anapparatus according to the invention associated with a textile machine,the latter being only partially represented;

FIG. 5 shows an exploded detail of the apparatus shown in FIG. 4;

FIG. 6 shows a front view of the apparatus and of the machine shown inFIG. 4;

FIG. 7 shows a broken perspective view of a preferred embodiment of anapparatus according to the invention associated with a textile machine,the latter being only partially represented;

FIG. 8 shows a left lateral view of the apparatus shown in FIG. 7;

FIG. 9 shows a top view of the apparatus shown in FIG. 7;

FIG. 10 shows a block diagram of an apparatus for controlling the weightand of some parts of a textile machine operatively connected to saidapparatus;

FIG. 11 shows a schematic of a loom containing an apparatus according tothe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to the figures mentioned above, the apparatus forcontrolling the weight according to the invention is generally indicatedwith the numeral 1.

Said apparatus is installed on a textile machine 2, and in particular ona circular knitting machine, comprising a fixed structure 3 under whichat least one needle bed 5 is turnably mounted around a vertical axis 4,said needle bed 5 consisting for instance of a cylinder and/or dialturning around stationary cans or vice versa.

A pick-up unit 6 for the fabric piece is placed under the needle bed 5,said group being equipped with a winding roll 7, in case the piece iswound into rolls, or with a cloth folder.

The fabric piece is dragged towards the winding roll 7 by at least atraction roll 8.

The pick-up unit 6 can turn around the vertical axis 4 integrally withthe needle bed 5 to which it is connected by means of arms 6 a, and itcomprises a pair of pillars 9 laterally placed, joined in their lowerportions by a pair of parallel bars 10 defining their base.

In an original way the apparatus for weight control 1 comprises weighingmeans 11 (FIGS. 3 and 5) adapted to weigh every single fabric piece anddirectly associated with the textile machine for the manufacture of saidpiece.

The weighing means comprise in their turn a weight sensor 12, forinstance a load cell, adapted to continuously detect the weight reachedby said piece during its manufacturing process and when wound in rollsor laps.

The weight sensor 12 is operatively connected to an electronic controlgroup 13 (FIG. 10), for instance a PLC, which can check the overallworking of the textile machine 2 and in particular of a main electricmotor 14 controlling the rotation of the needle bed 5 and the pick-upunit 6. The electronic control group 13 is advantageously connected, orat least put into communication, with a printer 15 producingself-adhesive labels containing at least the information referring tothe weight measured by the weight sensor 12. Moreover, a display 41showing the operator the progression of the measured-weight may beprovided. According to a first embodiment shown in FIGS. 1, 2 and 3, theweighing means 11 comprise, beyond the load cell 12, a support unit 16formed by a vertically sliding portion 17 and by a fixed base 18defining a guide for said sliding portion 17.

The latter supports the pick-up unit 6 and shows a portion 17 aoperatively contacted with a flexible wall 12 a of the weight sensor 12which is integral in its lower portion with a base plate 19 connected inits turn with the fixed structure 3.

Thus, introducing suitable joints into the arms 6 a connecting theneedle bed 5 with the pick-up unit 6 in order to avoid that the weightof the needle bed is transmitted onto said group, the weight sensor 12detects a load including the weight of said pick-up unit 6, whichrepresents the tare, and the weight of the fabric wound onto the windingroll 7.

The vertically sliding portion 17 comprises a support base 20 connectedwith the pick-up unit 6 and therefore turning integrally with said unitand with the cylinder or needle bed 5, a slide 21 slidably connected invertical direction with the fixed base 18, and turning coupling means 22placed between a vertical support shaft 23, constituting a lowerextension of the support base 20, and said slide 21. The turningcoupling means 22 consist of rolling-contact bearings supporting theaxial load undergone by the vertical shaft 23.

More to the point, the slide 21 is defined by a substantiallyglass-shaped cylindrical element housing the vertical shaft 23 andturning coupling means 22 and showing a bottom wall defining saidportion 17 a operatively contacted with the load cell 12.

The fixed base 18 comprises a substantially bush-shaped element 24,integral with ledges 24 of the fixed structure 3 and slidably coupledwith the slide 21 so that the central axis of said slide 21 andtherefore the axis of the vertical shaft 23 coincide with the verticalaxis 4 of the cylinder or needle bed 5.

Between the fixed base 18 and the slide 21 anti-turning means 25 areprovided, said means including a threaded plug 26 introduced into aradial hole of the fixed base 18 and showing a head 26 a housed in avertical groove 27 of the slide 21.

The slide 21 shows on its outer side a ring-shaped abutment extension 21a abutting against an upper edge 18 a of the bush-shaped element 18 soas to define a lower run end for the vertical translation of the slide21.

The abutment extension 21 a is normally detached of some millimetersfrom said upper edge 18 a so as to allow the slide 21 to unload itsweight onto the load cell 12.

The above-mentioned support base 20 comprises a circular plate 28integral in its lower portion with the vertical shaft 23 and a pair ofelongated elements 29 peripherally welded to the circular plate 28.

Said elongated elements 29 are connected with the parallel bars 10defining the base of the pick-up-unit 6.

According to a second embodiment of the present invention shown in FIGS.4, 5 and 6, the apparatus for the weight control 1 is placed along thepair of pillars 9, below the end supports of the winding roll 7 or ofthe cloth folder. As can be seen in FIG. 4, each pillar 9 is dividedinto two portions, an upper portion 9 a and a lower portion 9 b. The endsupports of the winding roll 7 are mounted onto the upper portions 9 a,in the same way as the traction rolls 9. The lower portion 9 b isintegral in its lower part with the pair of parallel bars 10 and it isconnected in its upper part to the arms 6 a by means of a support 40.

As shown in FIG. 5, the weighing means 11 of the apparatus for weightcontrol 1 are placed as a connection of each upper portion 9 a with thecorresponding lower portion 9 b. In this case two weight sensors or loadcells 12 are preferably provided, said sensors or cells beingoperatively mounted between said portions 9 a and 9 b so as to enableweight measurement of the first portion 9 a, of the traction rolls 8, ofthe winding roll 7 and of the picked up piece. Each load cell 12 carriesout an independent weight measurement. Weight can therefore be detectedby only one load cell.

The load cell 12 is fixed in its lower portion with an upper end 32 ofthe lower portion 9 b, for instance by means of at least a first screw37 engaged into at least a first through hole 30 of the upper end, andinto at least a first blind hole 36 in the load cell 12.

In its upper portion the cell shows a flexible wall 12 a integral with alower end 31 of the upper portion 9 a, for instance by means of at leasta first screw 35 engaged into at least a second through hole 33 of thelower end 31, and into at least a second blind hole 34 in the load cell.

It is also provided for a support element 39, consisting for instance ofa support bolt engaged into a third hole 38 on the upper end 32 of thelower portion 9 b. Said support is not usually in contact with the lowerend 31, but it supports the upper portion 9 a when the load to bemeasured is over a certain safety value beyond which the load cell 12could be damaged. The support 39 acts in practice as a run end.

According to a preferred embodiment of the present invention shown inFIGS. 7, 8 and 9, the apparatus for weight control 1 is placed in aprotruding position outside the machine, by means of a pair of supportarms 42 extending from the pair of pillars 9 respectively. Both supportarms 42 house the weighing means 11, advantageously carried out by meansof load cells 12.

The end supports 43 of the winding roll 7 or of the cloth folding reston both load cells 12, so as to allow said cells to detect only theweight of the winding roll 7, of the supports and of the fabric piece.

Advantageously, it could be provided for suitable support elements 39,analogous to those described in the second embodiment, in order toprotect such load cells 12.

As can be seen from FIGS. 7 and 9, the machine is advantageouslyprovided with three traction rolls 8, preferably located on the samehorizontal plane as the winding roll 7, between which the fabric pieceis introduced before reaching the winding roll 7. The vertical pullingstrength determined by the fabric piece during its manufacturing stageis thus unloaded onto the traction rolls 8. It can thus be avoided thatsaid pulling strength is transmitted to the winding roll 7, which wouldaffect the weight detected by the load cells 12.

Moreover, at least one of sand winding rolls 7 or traction rolls 8 canbe provided with two circumferential grooves 44 carried out on the outeredges of the folded fabric piece. Advantageously, as shown in FIG. 7,the central traction roll 8, i.e. the one absorbing the pulling strengthof the piece, is provided with grooves 44 on its ends and on the outeredges of the folded fabric piece. These grooves allow to avoid theformation of a permanent fold in the folded tubular fabrics on theiredges.

The working of an apparatus according to the invention, which has beendescribed above mainly from the structural point of view, is thefollowing.

In the first case the load cell 12 continuously detects the weight itsupports by means of the sliding portion 17 of the support unit 16. Inthe second case the cell directly detects the weight of one of the upperportions 9 a of the pair of pillars 9. In the third and preferred formof embodiment the load cell directly detects only the weight of thewinding roll 7, of the end supports 43 and of the piece.

In all the embodiments shown the detected weight increases with thepiling up of the fabric piece on the winding roll 7. The value of suchweight is transmitted from the load cell 12 to the PLC 13 by means of asignal constituted by an electric voltage. This voltage is comparedwithin the PLC with a preset reference voltage, corresponding inpractice to the desired weight the fabric piece should have aftermanufacturing.

When the measured weight reaches a threshold value, the display showsthe operator the weight progression so as to simplify its control.

When the voltage coming from the weight sensor 12 gets near the value ofsaid reference voltage, the PLC sets the procedure required to stop thetextile machine so that the latter stops production exactly on reachingthe pre-established weight by the fabric piece formed. It is nowpossible to carry out a new more precise weight measurement with themachine in a still status and possibly to provide a further advancementof said piece until the desired value is reached.

The detected weight and any other information sent to the PLC by thesensors of the machine and/or set by the operator, such as moisture, thekind of yarn used, possible interruptions of production corresponding tomanufacturing defects, are immediately written down on adhesive cardsissued by the printer 15.

Obviously, the calculation and setting of the desired fabric eightshould consider the tare, constituted by the weight of all the partsresting on the weighing device, from which—though only in the first twoembodiments—the weight corresponding to the pulling strength exerted bythe needle bed onto the piece should be subtracted.

It is obviously possible to provide for other embodiments of the presentinvention. For instance, the weight sensor 12 can be located in such aposition as to detect loads exerted onto the connecting arms 6 a, thusweighing a hanging load.

The present invention can advantageously and similarly be applied alsoto a loom 45 or any other textile machine for which it could be usefulto weigh the yarn or fabric produced in the manufacturing process.

As can be seen from FIG. 11, a fabric piece 46 is produced with the loom45, said piece being wound around a winding roll 47 supported on its endsupports 49 by a pair of support arms 48.

Also in this case load cells 50 implementing an apparatus forcontrolling the piece weight are placed between the support arms 48 andthe end supports 49 of the winding roll 47.

The invention implements a new method which is also an integral part ofthe present patent.

Said method consists in weighing each folded or wound fabric piece nearthe textile machine manufacturing said piece after the latter has beenproduced.

The method further provides to associate each produced piece with aprinted element providing at least the information concerning the weightassigned to said piece. Advantageously, the weighing of each pieceproduced by a textile machine is carried out continuously, at leastduring the final manufacturing stage, so as to compare the detectedweight, increasing during manufacturing and pick-up of said piece, witha pre-established reference weight.

It is preferably provided for a display located near the machine, whichshows the progression of the weight when it reaches a first referencevalue.

The textile machine is stopped when the detected weight reaches saidpre-established value.

Since during the working of the machine the weight measurement isslightly different from the measurement with the machine in a stillstatus, in order to get a more precise measurement it is advantageouslypossible to provide a first machine stop on reaching a pre-establishedweight value near the desired one. After said measurement is carried outthe machine is re-started until the desired weight, which can be furtherchecked with the machine in a still status, is reached.

The invention has important advantages.

First of all, the weight of each piece corresponds with a high degree ofprecision to the pre-established weight, since the latter and no otherparameters defines the end of the manufacturing and folding or windingstages of said piece.

It should be pointed out that the cards identifying each piece accordingto its weight and other parameters deemed as necessary to distinguish itare immediately available at the end of its manufacturing and cantherefore be applied onto said piece, thus avoiding mistakes andinformation exchanges among different pieces.

It should further be pointed out that the continuous weighing of eachpiece during its manufacturing can be used for a remote monitoring ofproduction for several textile machines, so as to know exactly in realtime the quantity and kind of produced material.

Moreover, said information, suitably processed, can be used forstorehouse control and for the related certification forms.

Other important advantages can be obtained, in particular, in thepreferred embodiment of the invention, shown in FIGS. 7, 8 and 9.

First of all, as a matter of fact, a great improvement in weighingprecision and reliability can be pointed out, due to tare reduction, thetare consisting only of the winding roll 7 and of its supports, and tothe elimination of the vertical pulling strength of the piece which hadto be subtracted from the tare weight.

Moreover, the preferred embodiment of the invention simplifies theprocess of removal of the loaded winding roll 7 and its replacement withanother roll, thus simplifying the operator's intervention and making itpossible to place a pick-up trolley directly under the roll and possiblyto automate said operation.

A further advantage of the present embodiment is a reduction ofpermanent folds on the edges of tubular fabric, since thanks to suitablegrooves 44 made on the traction rolls 8, the usual flattening of saidedges can be avoided. A final advantage of the preferred embodiment isthe possibility to obtain machines with reduced height, thanks to thefact that the winding roll and the traction rolls are on the samehorizontal plane instead of being on the same vertical plane. Thisgreatly simplifies the visual check of the process carried out in themachine by the operator, since the introduction of the yarns into thecylinder is executed at such a height as to be visually accessible alsoto short people.

In practice, the weighing apparatus according to the invention allows toimprove the handling of products of textile machines from an operationaland organizational point of view, thus simplifying the various operatingstages and reducing execution times.

1. An Apparatus for controlling the weight of fabric produced by atextile machine, said textile machine being of the type comprising apick-up unit (6) for a folded or wound fabric piece characterized inthat the apparatus comprises: weighing means (11) for providing a valueof weight for each fabric piece associated with the textile machine (2)dedicated to manufacture of said piece; said weighing means comprisingat least a weight sensor (12) detecting the weight reached by said pieceduring its manufacturing and pick-up stages, operatively connected to anelectronic control group (13) to check functionality of the textilemachine; and a support unit (16) consisting of at least a verticallysliding portion (17) supporting said pick-up unit (6) and a surface (17a) operatively contacted with said weight sensor (12), and a fixed base(18) defining a guide for said sliding portion (17).
 2. Apparatusaccording to claim 1, characterized in that said vertically slidingportion (17) of the support unit (16) comprises: a support base (20)connected to the pick-up unit (6) and turning together with the latterintegrally with a needle bed (5) of the textile machine (2), a slide(21) slidably connected in vertical direction to said fixed base (18),and turning coupling means (22) around the vertical turning axis (4) ofthe pick-up unit (6) placed between said support base (20) and saidslide (21).
 3. Apparatus according to claim 2, characterized in thatsaid support base (20) connected to the pick-up group (6) shows in itslower portion a vertical support shaft (23), and in that said turningcoupling means (22) are connected to said vertical shaft (23) andsuitable to support the axial load exerted onto said shaft.
 4. Apparatusaccording to claim 3, characterized in that said slide (21) is definedby a substantially glass-shaped element housing said vertical supportshaft (23) and said turning coupling means (22), said glass-shapedelement showing a bottom wall defining said area (17 a) operativelycontacted with the weight sensor (12).
 5. Apparatus according to claim4, characterized in that said fixed based (18) comprises a substantiallybush-shaped element slidably coupled with said glass-shaped slide (21),and in that anti-rotation means (25) are placed between said bush-shapedelement (18) and the slide (21), said anti-rotation means (25) suitableto transmit the vertical translation direction to said slide (21). 6.Apparatus according to claim 5, characterized in that said glass-shapedslide (21) shows on its outer portion an abutment extension (21 a)abutting against an upper edge (18 a) of said bush-shaped element (18)to define a lower run end for the vertical translation of said slide(21).
 7. Apparatus according to claim 3, characterized in that saidsupport base (2) comprises a circular plate (28) integral in its lowerportion with said vertical support shaft (23) and a pair of elongatedelements (29) peripherally integral with said circular plate (28) andengaging a pair of parallel bars (10) defining the base of said pick-upunit (6).
 8. Apparatus according to claim 1, characterized in that saidweight sensor (12) consists of a load cell showing a flexible wall (12a) in contact with said sliding portion (17) of the support unit (16).9. An Apparatus for controlling the weight of fabric produced by atextile machine, said textile machine being of the type comprising apick-up unit (6) for a folded or wound fabric piece characterized inthat the apparatus comprises: weighing means (11) for providing a valueof weight for each fabric piece associated with the textile machine (2)dedicated to manufacture of said piece; a winding roll (7) to pick upthe piece; at least a pillar (9) divided into an upper portion (9 a)supporting said winding roll (7), and a lower portion (9 b); a supportelement (39) integral with said lower portion (9 b) and placed so as tosupport said upper portion (9 a) instead of said weighing means (11)when the weight is over a given safety value; said weighing means (11)being operatively placed between said upper portion (9 a) and said lowerportion 9(b).